/*
Write an algorithm
to determine
if a
number is "happy".
A happy
number is a
number defined
by the following process: Starting
with any positive
integer, replace
the number by the sum
of the squares
of its digits,
and repeat the process
until the number equals 1 (
where it will stay),
or it loops endlessly
in a cycle which
does not include
1. Those numbers
for which this process ends
in 1 are happy numbers.
Example:
19 is a happy
number
1^
2 +
9^
2 =
82
8^
2 +
2^
2 =
68
6^
2 +
8^
2 =
100
1^
2 +
0^
2 +
0^
2 =
1
每次计算出的和值使用hash表存储，通过查看hash表判断是否有环
*/
using namespace std;
class Solution {
public:
bool isHappy(int n) {
if(n==
0)
return false;
unordered_map<int,int> m;
while(n!=
1)
{
if(m[n]++ ==
1)
return false;
int res=n;
n=
0;
while(res)
{
n+=(res%
10)*(res%
10);
res/=
10;
}
}
return true;
}
};
int main()
{
Solution mys;
int n=
34;
cout<<mys.isHappy(n)<<endl;
return 0;
}
